Carl hoepfner



UNITED STATES PATENT errors,

CARL HOEPFNER, OF GIESSEN, GERMANY.

ANODE FOR ELECTROLYTICAL APPARATUS.

SPECIFICATION forming part of Letters Patent No. 546,328, dated September 1'7, 1895.

Application filed March 26, 1894. Serial No. 505,179. (lie Specimens.)

To all whom it may concern.-

Be it known that I, CARL HOEPFNER, a subject of the German Emperor, residing at Giesson, in the German Empire, have invented certain new and useful Improvements in Anodes for Electrolytical Apparatus; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention has relation to anodes for electrolytical apparatus, and more especially to anodes used in the electrolytical production of chlorine or in the electrolytical decomposition of the halogen salts of the heavier and lighter metals or metal radicals, such as ammonium, and in the direct production of copper by electrolysis, as well as in the electrolytical treatment of acids and alkalies, as sodium or potassium chlorid, and in the electrolytical treatment of cyanogen combinationsin fact, in all cases where it has heretofore been found necessary to use carbon anodes exclusively. It is well known that the carbon an odes when artificially produced are of short duration, while anodes constructed of retort carbon are very costly, so that the use of either kind of anodes materially increases the expense of the electrolytical production or treatment of such substances or bodies as above referred to.

- The object of my invention is to provide an anode of greater durability than an artificial carbon anode, and even cheaper than the latter, and hence considerably cheaper than an anode made of retort carbon, by constructing the anode of aconductive substance the surface of which contains a great proportion of silicium (practically not less than ten per cent.)-as, for instance, ferro-silicium, with about ten per cent. silicium or more. Such anodes not only possess the required power or property of resistance and conductivity, but are also extremely cheap and adapted to re ceive any desired shape or form.

I am aware that ferro-siliciiim has been used for the cathodes of Bunsen elements Where nitric acid was employed as an active or exciting agent or for the purpose of obtaining a conserving or preserving action of the electric current. It is well known that pure or con centrated nitric acid does not appreciably attack iron and does not attack aluminium, yet neither metal can resist the action of chlorine or hydrochloric acid, while either of the compounds above referred to is proof against both. Furthermore, in the electrolytical production of chlorine a metallic anode at which chlorine is set free is readily destroyed, and more readily than an anode in the nitric acid of a galvanic element.

In' carrying out my invention I make the anode either wholly or partially of ferro-silicium. WVhen made wholly of ferro-silicium, it may be cast or otherwise formed to the desired shape, or a suitable conductive metal or other conductive substance, as carbon, may be coated or plated with ferro-silicium, either electrolytically or otherwise, or the electrode may be constructed of a compound containing ferro-silicium as a compound of the latter metal and carbon intimately mixed and reduced to a plastic condition, from which the electrode is made by molding or otherwise. On the other hand, a suitable conductive metal may be combined with silicium, and the proportion of the latter so regulated as to impart to the compound the required property of resistance. Thus, for instance, iron may be reduced to a pulverulent condition by dissolution and precipitation in any wellknown manner, and then intimately mixed with silicium in sufiicient quantity to render the compound proof against the action of chlorine or acids or other substances or bodies liable to act injuriously upon the iron. The conversion of the iron and silicium into a plastic bodyor the conversion into such a body of a mixture of ferro-silicium and carbon may be, and preferably is, effected by means of paraffin or a similar substance. Pure silicium may be deposited upon an iron or nickel anode for instance, for the purpose of providing a protective coating to the surfaces of the anode exposed to the action of chlorine or other agent that would otherwise destroy the said anode. In either case I obtain an anode that contains on its surface in minimo about ten per cent. silicium, and is not only very cheap, but has the required property of resisting the action of the bodies hereinabove referred 170.,

Having thus described my invention, what I claim as new therein, and desire to secure by Letters Patent, is-

1. An anode for electrolytical apparatuses, consisting of a conductive substance, the surface of which anode contains in minimo about ten per cent. silicinm, so as torender such anode proof against the action of liquids or gases to which it may be exposed, particularly against the action of chlorine.

2. An anode for electrolytical apparatuses, consisting on its surfaceofa compound of sihcium and another conductive metal in such 

